September 2002: Russia begins preparations for a reactor worth $800m near Iran's south-western port of Bushehr. The plan at this stage is to have the plant up and running by the end of 2003.

December 2002: The US accuses Iran of seeking to develop a secret nuclear weapons programme and publishes satellite images of two nuclear sites under construction at Natanz and Arak.

February - May 2003: The UN's International Atomic Energy Agency (IAEA) conducts a series of inspections in Iran. The country confirms that there are sites at Natanz and Arak under construction, but insists that these - like Bushehr - are designed solely to provide fuel for future power plants.

16 June, 2003: IAEA head Mohammed ElBaradei states that inspections showed "Iran failed to report certain nuclear materials and activities" and urges "co-operative actions" on the part of Iran. However the report does not declare Iran in breach of the Non-Proliferation Treaty.

EU foreign ministers meanwhile call on Iran to allow tougher nuclear inspections.

19 June, 2003: White House spokesman Ari Fleischer refuses to rule out the "military option" in dealing with Iran.

July 2003: IAEA begins a fresh round of inspections in Iran.

September 2003: Washington says Iran is not complying with international non-proliferation accords but agrees to support a proposal from Britain, France and Germany to give the country until the end of October fully to disclose nuclear activities and allow surprise inspections.

13 October, 2003: Russia says it has delayed plans to start up a nuclear reactor in Iran by a year but stresses this is for technical reasons, not because of external political pressure.

19 October, 2003: Officials in Tehran hold negotiations with IAEA envoys on signing an agreement to allow tougher inspections of its nuclear facilities.

21 October, 2003: Iran's Foreign Minister Kamal Kharrazi promises "total transparency" over the country's nuclear programme during talks with his counterparts from Britain, France and Germany.